The Sixteenth United States Census, conducted by the Census Bureau, determined the resident population of the United States to be 132,164,569, an increase of 7.3 percent over the 1930 population of 123,202,624 persons. The census date of record was April 1, 1940. A number of new questions were asked including where people were 5 years before, highest educational grade achieved, and information about wages. This census introduced sampling techniques; one in 20 people were asked additional questions on the census form. Other innovations included a field test of the census in 1939.

if at work, whether in private or non-emergency government work, or in public emergency work (WPA, CCC, NYA, etc.)

if in private or non-emergency government work, hours worked in week

if seeking work or on public emergency work, duration of unemployment

occupation, industry and class of worker

weeks worked last year

wage and salary income last year

In addition, a sample of individuals were asked additional questions covering age at first marriage, fertility, and other topics. Full documentation on the 1940 census, including census forms and a procedural history, is available from the Integrated Public Use Microdata Series.